Flight attitude and movement indicator



Sept. 29, 1936. D. B. HOWARD ET AL 2,055,495

FLIGHT ATTITUDE AND MOVEMENT INDICA'IfOR Filed July 18. 1950 4 Sheets-Sheet l FIQIE INYEUTORJ. Kmw/tru .d. WOLF" UDLEY 8. HOWARO Arron er.

Sept. 29, 1936 D. B. HOWARD ET AL FLIGHT ATTITUDE AND MOVEMENT INDICATOR 4 Sheets-Sheet 2 Filed July l8. 1930 I in llvvz lv'rona WOLFE HOWARD Ins-Aw: 1-11 B.

Sept. 29, 1936. b. B. HOWARD ET AL 2,055,495

FLIGHT ATTITUDE AND MOVEMENT INDICATOR Filed July 18. 1930 4 Sheets-Sheet 3 HEM/Vern 5. W'OLFE DUDLS) B. HOWARD @ZKWYW/W P 1936- D. B. HQWARD ET AL 2,055,495

FLIGHT ATTITUDE AND MOVEMENT INDICATOR Filed July 18. 193 4 Sheets-Sheet 4 REVERSIBLE MOTOR k luvswrons:

lfswlv TH 5. h/ogrz F re- 1K Duoaar B. Hon 1R D Patented Sept. 29, 1 936 PATENT OFFICE FLIGHT ATTITUDE AND MovmmuT mmcATon Dudley B. Howard, Riverside, Calif., and

Kenneth B. Wolfe, Dayton, Ohio application July 18, 1930, Serial No. 468,964

1: Claims. (eras-204) (Granted under the act of'Marcli a, 1883, at amended April 30,1928; s'zo o. e. 751) The invention described herein may be manu factured and used by or for the Government for governmental purposes, without the payment to me ofany royalty thereon.

5 This invention relates to flight indicators for use in'airplanes and in particular to such ins'truments of the artificial horizon type designed for use in "blind" flying in fog or clouds when the actual'horizon is invisible.

l0 The primary object in view is to provide a flight indicator which, in operation, will present to the pilot a natural picture of the attitude of his aircraft that changes during flight to reproduce faithfully the. successive changes of attitude.

A furtherobject is to provide a flight indicator I of this type which, in'addition to indicating attitude will indicate the nature of movement of the aircraft about-its three major axes, such as Properly banked turning movement, slipping, skidding, stalling," and; excessive speed.

1 Other advantages of the invention should become apparent as the following specific description is read in. connection with the accompanying drawings, in whichp 25 Figure I 'is a vertical section of a simplified form of the instrument, showing means for indicating attitude alone;

Figure 11 is a fragmentary elevation of the face of the instrument illustrated in Figure I showing the horizon and aircraft representations in a relationship denoting straight and level flight; Figure 111 is a fragmentary vertical section of a. modified form of the device wherein the ar-n rangement of primary indicating elements is re-' versed to cause pivoting movement of the aircraft representation instead of the artificial hori-.

zon;

, Figure IV is a fragmentary elevation of the face of the instrument depicted in Figure III, 40 showing indication of straight and level flight;

, Figure V is a similar view showing indication of a climbing right turn;

Figure V1 is a diagrammatic perspective view of the three primary indicating elements of the 5 preferred form of the device in positions indicating straight and level flight;

Figure VII is a fragmentary elevation of the face of the preferred form of instrument, showing indication of a properlybanked left turn 50 without gain or loss of altitude;

Figure ,VIII is a fragmentary vertical section of the preferred form of instrument, showing its primary elements in positions indicating straight and level flight;

- Figure TX is a dia rammatic assembly view,

' mination of the dial to denote anadvanced stage showing the primary indicating and control elements, including those located outside the instruof stalling, such as immediately precedes falling into a spin. In Figures I and II, a simplified form of instrument is illustrated. In this device, attitude in flight is indicated by gyrostats throughthe relative adjusting 'of two primary indicating elements, which are visible through a view opening I in the face of the instrument case 2. These elements are the artificial horizon representation 3 and the miniature aircraft representation 7 The artificial horizon may be produced conveniently by painting the lower half of a circular disk 5 black, blue, or any "color which will be distinguishable in appearance from the upper half, which is preferably white. The line of demarkation between the dark and light semicircles constitutes the artificial horizon.

-Disk 5 should be mounted so as to be axially pivoted. A convenient arrangement is to connect it for rotation with the gimbal'frame G of a turnresponsive gyrostat 'l of the restrained type ordinarily used in flight indicators. This gyro. therefore, is disposed with its spin axis 8 normally parallel to the lateral axis of the aircraft in which-the instrument is used. The gimbal 9' *0 should be parallel to the longitudinal aircraft axis. The gyro is adapted to be driven by air blast in the direction of the arrow in the usual manner. Further details of construction of the gyro will not be described, because no invention in the same is claimed.

The aircraft representation I is shown mounted on a stem l0, whichisradially movable with respect to the axis of disk 5 in bearings II. The lower end of the stem Ill may-be connected, as 5 shown, by link I! with the lever arm I 3 of the usual pitch-responsive gyro I. This gyro is of the usual non-pendulous type as shown in Patent No. 1,812,503, June 30, 1931 and does not require detailed description. It will be noted that its to the vertical aircraft axis.

spin axis I5 is normally parallel to the longitudinal aircraft axis and its gimbal axis l6 parallel The stem II) should be of such length that the aircraft representation 4 will be on a level with the center of the artificial horizon 3 when the actual supporting aircraft is in level position fore-and-aft. In the operation of the instrument just described, the turn-responsive gyro I maintains the artificial horizon parallel to the lateral aircraft axis when the aircraft is flying straight. When a turn to the right is made, the resulting'precession of the gyro will cause the disk 5 to oscillate in counter-clockwise direction to bring the artificial horizon into the dotted line position 3a. This action produces an angular arrangement of the miniature aircraft representation with respect to the artificial horizon which gives the usual appearance of the banked attitude of an' aircraft when viewed in connection with the actual horizon and ground plane. A turn to the left will cause reverse oscillation of the disk in clockwise direction into a position wherein the artificial horizon will assume the position of dotted line 317.

Pitching of the aircraft will cause the miniature aircraft 4 to move above or below the artificial horizon to correspond with-climbing and gliding movements of the actual aircraft, respectively, through the action of the gyro 14'.

In Figures III to V, inclusive, the connection of the artificial horizon and miniature aircraft representations with the two gyros reversed, -the former being connected with the pitch-respon-.

sive gyro and the latter with the turn-responsive gyro, in this instance. The artificial horizon representation 3c is preferably formed by the upper edge of a rectangular plate 5a mounted for verti cal reciprocation in bearings Ila and connected by rocker member llb and link l2 to leverarm ,l3 of the pitch-responsive gyro (not shown). 0n the level fore-and-aft-attitude of the actual air-= craft, the artificial horizon will be maintained on a level with the gimbal axis 9 of the tum-responsive gyro.

The aircraft representation 4a is disposed in alignment with the gimbal axis 9 of the turn-responsive gyro at all times. It is supported by arched stem I1 projecting from disk l8 attached to pivot shaft I9 mounted in a bearing in bracket 20. Disk "3 is concentric with the gimbal axis of the gyro so as to cause oscillation of the aircraft representation about that axis. Intermediate gears '2l connect gear 22 keyed to shaft l9 with 'an annular geared rack 23 attachedfixedly to the gimbal frame concentric with its rotational axis. The gearing will cause reversal in direction of oscillation of the aircraft representation 7 with respect to the gyro gimbal frame.

In operation, simulated banking of the miniature aircraft in the same direction as the actual aircraft banks in a turn will be produced. For instance; in a tumto the right, the gimbal frame of the turn-responsive gyro will-oscillate in counter-clockwise direction. Resulting oscillation of the miniature aircraft will lie clockwise as indicated in Figure V. In this figure a climbing turn is indicated. Elevation of the nose of the aircraft in climbing causes the pitch-responsive gyro to precess in a direction which results in downward thrust of the stem 5a, which is opposite 'to the direction of movement of the adjacent end of lever arm 13. This action lowers the artificial horizon beneath the miniature aircraft and produces the visual efiect of climbing above the horizon.

The primary indicating elements employed in the improved device are three in number, instead of merely two as in the simplified form. In addition to an artificial horizon representation, and a miniature aircraft representation, there is a representation of sky scenery such as appears above the horizon in flight. All three representations are preferably independently movable and disposed in appropriate positions adjacent to each other. A convenient arrangement is illustrated diagrammatically in Figure VI.

In the figure just mentioned, the sky scenery representation 24 is depicted on a band 25 of opaque material. The artificial horizon 3d is represented by the upper edge of an opaque plate 51), which masks a portion of the sky scenery reresentation. The miniature aircraft representation 4b is depicted on a transparent plate 26 disand band 25. Plates 28 and5b should be in substantial parallelism with the exposed portion of band 25.-

Various alternative arrangements and movable relationships of the three primary indicating elements may be chosen in practice, but a simple, convenient embodiment of the inventive idea isdisclosed in Figures VIII and 1K in particular. In accordance therewith, the band 25 is endlessjn form and mounted on spools 21 and 28, which are disposed so that the stretch of band nearest the view opening Ia will always be parallel thereto. Spool 21 is adapted to be secured fixedly to a driving shaft 29 extending vertically from a reversible electric motor 30, which has been chosen as the prime mover for the band 25. Spool 28 idles in bearings 3|.

The sky scenery has been represented by banks of clouds extending throughout the length of the band 25 and located principally in the upper half of the same. The scenery may be of any nature which will permit ready discernment of any translatory movement along the artificial horizon.

Plate 5b, the upper edge of which represents the artificial horizon, is mounted for vertical reobjects. The result in view is the optical illusion of simultaneous horizontal transl tion of both the sky scenery and the ground presentation.

The. miniature aircraft is epresented on transparent plate 26 by etc painting, or in any other convenient mariner. The plate is shown mounted in a rim 34 supported by arched stem 35 in a position between the plate 5b and the view opening. Stem 35 is attached to a rock shaft 35 pivoted in bearing 3'! concentric to the view opening. The aircraft representation 4b should be in alignment with the pivotal axis of shaft 36 so that it may oscillateabout the axis.

25 posed in super-imposed relation to the plate 5b.

The ultimate objeetof the above described ar rangement of the three. primary indicating elements is the optical illusion of horizontal translation of the miniature aircraft along the artificial direction to actual translation of the sky scenery.

Rock shaft 35 of the shifting means for the aircraft representation is connected with the' gimbal frame 311: of a bank-responsive gyro 38 by bevel gears 39 and 40. This gyro is similar in type to the pitch-responsive gyro in that it is non-pendulous. It is disposed with its gimbal axis vertical and its spin axis normally parallel to the lateral axis of the actual supporting aircraft. Banking of the aircraft in a given direction results in banking of the miniature aircraft representation in the same direction. For instance, banking in counter-clockwise direction as in a left turn produces the corresponding simulated banking of the miniature aircraft illustrated in Figure IX. V

Plate 511, which affords the artificial horizon, has its operating stem connected indirectly with a. lever arm corresponding to lever l3 (Fig. 3) of the pitch-responsive gyro. It is desired that there shall be a slight degree of play between the plate and lever arni to permit vibration of the plate in its bearings, bymeans which will be described presently, to indicate stalling. For this purpose, the stem is divided into telescopic secresponds to the member l lb of Figure III. The

remainder-of the connecting mechanism which 21 of the sky scenery shifting mechanism. is.

adapted to be connected electrically with a source of current 42 by a reversing switch 43 having a movable contact member 45 that is.

maintained normally in neutral position, wherein all motor circuits are open, by. usual turn-responsive gyro whosegimbal ring is shown at lb with which it is directly connected, as shown particularly in Figure VDI. The construction and wiring arrangement is such that a turn to the left in flight will throw the movable contact member clockwise and causerotation of the motor in a direction which will translate the sky scenery representation in a direction outward from the turn indicated in Figure IX, The arrow indicates the direction of translation of scenery. Turning to the right will cause the movable switch member 45 to be thrown by the turn-responsive gyro 'lbin the reverse direction and will reverse the motor circuit to produce appropriate translation of scene y'outward fromthe turn in the new direction. The switch will be restored to normal open position by return to straight flight.

In order to indicate skidding on a turn, means are. provided for throwing the reversing switch contact member 45 and a movable holder 45 for y the contact plates 41 which are adapted to bridge the stationary contact points 48. Yieldable springs 49 are interposed between the arm 45 and 5 branches of the holder 45 and provide a yieldable connection therebetween. The common core 50 is connected operatively with the holder 45. The solenoid coils 5| and 52 are connected in normally open electric circuits with two separate sources of current 53 and 54, respectively. The direction of winding and polarity of the circuits are such that energization of solenoid 5| will cause the reversing switch member 45 to be thrown in counter-clockwise direction (Figure IX), whereas energizationof solenoid 52 will produce clockwise movement of the switch member .45. Normally open switches 55 and 55 are adapted to close the respective circuits in which solenoid coils 5| and 52, are connected to energize the same.

Various agencies may be selected for automatic the switches 55 and 55. The box is divided into two air-tight compartments 58 and 59. A static tube S extends from compartment 58 laterally toward the right wing tip of the aircraft and another static tube S extends laterally from the other compartment toward the opposite wing tip. Pitot tubes P and P extend from diaphragm boxes 50 and 5| toward the right and left wing tips respectively. Diaphragms 62 and 53, which are moved inward by difierences in pressure in the corresponding tubes are adapted to close the switches 55 and 55, respectively. skidding" toward the right will, therefore, close switch 55 and skidding toward the left will close switch 55.

- Figure X shows the indication of skidding on a left turn. Although the miniature aircraft is banked toward the left it appears to be skidding outward from the turn, due to translation of sky [scenery toward the left. This reverse movement zen-representing plate 5b for rectilinear movement therewith. The solenoid coil is connected electrically with a source of current. by two normally open parallel circuits. One circuit ineludes switch 55. of control'box 51 and a supplementary switch 51, which is adapted to be closed by the arched stem 35 of the miniature aircraft representation rim whenever the actual aircraft is banked to the right. The solenoid coil is connected by the other branch of the circuit with ,the source 55 through switch 55 and supplementary' switch'58, adapted to be closed by stem 35, when the aircraft is banked to the left, as indicated in Figure IX. C011 55 iswound so thatenergization of the same will thrust the stem lOa upward to move the artificial horizon abovethe miniature aircraft. The impression aflorded will,

be that of slipping.

Referring to Figure IX, it will be noted that switch 58 is closed in the left turn simulated. While the turnis properly executed, the sky scenery will move along the artificial horizon in a direction outward from the turn. Should the aircraft commence to slip inward. on the turn,

switch 58 will be closed automatically by the Pitot-static control mechanism. Energization of solenoid 65 will result and the artificial horizon will be elevated in the manner previously described. At thesame instant, the circuit of the reversible motor 30 will be broken by an automatic switch 69, through energization of its electromagnet 10, the coil of which is connected in the circuit of solenoid 65. A spring normally maintains the automatic switch 69 closed. Stoppage of motor 30 causes the sky scenery of the indicating elements to become stationary. The visual efiect is illustrated in Figure XI.

It seems desirable to indicate stalling by vibration of the artificial horizon to simulate wavering and instability of the aircraft. In order to allow for reaction time in averting a spin, means have been provided for giving a preliminary indication of serious loss of flying speed and a final indication distinguishable from the first at the advanced stage of stalling when the aircraft is on the verge of spinning. The final stage is signailed by the illumination of the indicating elements with a red light.

"with these purposes in view, an airspeed indicator of usual type, which may be the one included in the regular equipment of the aircraft instrument board, is utilized as the stall-responsive agency for producing the indicating signals just mentioned. A circuit-closer is attached to the air speed indicatorin any convenient manner so thatmovement of the indicating pointer to any predetermined critical air speed will cause an appropriate circuit to be closed. In the present instance, a movable contact arm H is movable in unison withtheindicating pointer I? and is adaped to traverse three stationary contact points I3, 14, and 15. Contact point 13 should be located adjacent to the air speed indicator on the instrument scale which represents actual stalling speed of the particu ar aircraft on which the instrum ent is to be used. Contact point I4 is located adjacent to a predetermined reading which approaches stalling speed by an interval suificient for reactiontime. Contact point 15 is disposed adjacent to a reading which represents an' air speed nearly as high as maximum safe speed for the particular aircraft. The movable contact arm II is connected electrically with onepole 'of a source of current 16. Contact point 14 is connected with the opposite pole of source 16 through solenoid coils 65 and an interrupter 11. Contact points'l3 and 15 are connected with the same pole ofsource 16 as that to which contact point 14 is connected and includes a red light bulb 18 in this branch of the circuits The light bulb should be located in a suitable position to cast its colored light on the indicating elements 4b, b and 24 whenever the circuit is closed; A second bulb "adapted to produce white light is shown disposed in a similar position and connected in parallel with source 16 through a manual switch 80, by which its circuit may be closed at Movable contact ll first touches stationary contact H. The solenoid coil 65 is connectedwith source I6 and becomes energized intermittently due to the operation of interruption H, which rapidly makes and breaks the circuit. Vibration of the artificial horizon results, giving the visual effect shown in Figure XII. This is a preliminary danger signal. Simultaneously. with the vibraglare of light which should attract the pilot's attention if he has missed the preliminary indication. Overlapping of the stationary contacts 13 and 14 in the manner shown will cause vibration of the artificial horizon to continue during display of the red danger light. This will distinguish from mere display of the red light which occurs when movable contact H touches stationary contact at critically high speed.

We claim-- 1. A flight indicator comprising means for representing an artificial horizon, means for representing a miniature aircraft adjacent to the artiflcial horizon, means for representing sky scenery in appropriate relationship to the artificial horizon, means mounting the artificial horizon and miniature aircraft representations for relative angular movement and for rectilinear movement above and below each other, means responsive to banking and pitching movements in flight adapt-.

ed to cause relative movement of the miniature aircraft and artificial horizon representations simulating the changes in attitude of the actual supporting aircraft, means mounting the sky scenery representation for translatory movement along the artificial horizon representation in opposite directions, means responsive to turning movementin flight adapted to produce appropriate translatory movement of the sky scenery along the artificial-horizon outward from the indicated direction of turn, and means responsive to skidding movement outward on a turn adapted to reverse the direction of translation of the sky scene 2. i fiight indicator comprising means for representing an artificial horizon, means for representing a miniature aircraft adjacent to the artificial horizon, means mounting the artificial horizon and miniatureaircraft representations artificial horizon, means for representing sky scenery in appropriate relationship to the artificialhorizon, means mounting the artificial horizon and miniature aircraft representations, for

relative angular movement and for rectilinear.

movement above and below each other, means responsive to banking and pitching movements in flight and adapted to cause relative movement of Zthe miniature aircraft and artificial horizon representations simulating thechan'ges in attitude of ithe actual supporting aircraft, means mounting the scenery representations for translatory'movement along the artificial horizon representations inopposi'te ections, me ans responsive to turning moveine t in flight and adapted to produce appropriate translatory movement of the sky scenery along the artificial horizon outward from the indicated direction of turn, and means responsive to side .slipping movement and adapted to cause relative vertical movement of the aircraft and artificial horizon representations' simulating the slips.

4. A flight indicator comprising means for representing an artificial horizon, means for representing a miniature aircraft adjacent to the artificial horizon, means mounting the artificial horizon and miniature aircraft representations for relative angular movement and for rectilinear movement above and below each other, and means responsive to reduction of airspeed of flight to a point bearing a predetermined relationship to stalling speed and adapted to produce distinctive relative movement of the miniature aircraft and artificialhorizon representations.

5. A flight indicator comprising means for representing, an artificial horizon, means for representing a miniature aircraft adjacent to the artificial horizon, means mounting the artificial horizon and miniature aircraft representations for relative angular movement and for rectilinear artificial horizon representations to simulate wavering.

- 6. A flight indicator comprising means for representing an artificial horizon, means for representing a miniature aircraft adjacent to the artificial horizon, means mounting theartificial horizon and the miniature aircraft representations for relative angular movement and for rectilinear movement above and below each other,

means responsive "to banking and pitching move-' ments in flight and adapted to cause relativei movement of .the miniature aircraft and artificial horizon representations simulating the attitude of the actual supporting aircraft, and

means responsive to reduction of airspeed of flight to a point bearing a predetermined relationship resenting a miniature aircraft adjacent to the artificial horizon, means mounting the artificial horizon and miniature aircraft representatidns for relative angularmovement and for rectilinear movement above and below each other, means responsive tobanking and pitching movements in flight and adapted-to produce relative movement between the two. representations simulating the successive changes in attitude of the actual supporting aircraft, means for representing sky scenery in appropriate relationship to the artificial horizon, means mounting the sky seen ery representations for translatory movement along the artificial horizon representation in opposite directions, means responsive to; turning movement in flight and adapted to cause trans-9 latory movementof thesky scenery along the.

artificial horizon in'a direction outward from the turn, means responsive to slipping inward on. a turn adapted to cause relative vertical moveto interrupt movement-of the sky scenery translating means.

8. A. flight indicator comprising means for representing an artificial horizon, means for representing a miniature aircraft adjacent to the artificial horizon, means mounting the artificial horizon and miniature aircraft representations for relative angular movement and for rectilinear movement above and below each other, means responsive to banking and pitching movements in flight and adapted to produce relative movement between the two representations simulating the successive changes in attitude of the actualsupporting aircraft, means for representing sky scenery in appropriate relationship to the artificial horizon, means mounting the sky scenery representations for translatory movement along the artificial horizon representation in opposite directions, means responsive to turning movement in flight adapted to cause translatory movement 'of the sky scenery along the artificial horizon in a direction outward from the turn, means responsive to critical loss of flying speed and adapted to cause relative vertical movement of miniature aircraft and artificial horizon simulating wavering in flight, and means responsive to critical loss of air-speed and adapted to interrupt movement of the sky scenery translating means during indication of wavering.- .4

9. In combination, a turn indicator surface having a sky view thereon, gyroscopically conleft to right and vice versa upon turning of an aircraft to which. the turn indicator surface is attached, and a movable bank indicator includ ing a movable bank indicating element cooperatively and adjacently positioned in the same field of view as'said turn indicator surface for visual correlation therewith.

10. Inan aerial flight instrument the combination of a screen having depicted thereon the normal flight view in clear weather of the pilot of an aircraft, gyroscopic means for laterally moving the screento indicate the direction .of turn of the aircraft to which the instrument is attached, a wing-like inclinometer operatively mounted in'the same field of view" as the screen and in co-relation therewith, and a rise and fall indicating element supported'for movement in the same field of view as the inclinometer and screen and movable in a line transverse to the screen movement. a r

11. In a turn indicating instrument the combination of a supporting frame, relatively'spaced roller means on the frame operating on vertical axes, a screen rotatable over said roller means and extending therebetween so that the same may be wound between the roller means from left to right and vice versa, said screen on its forward surfacehaving a view similar to the pilot's view of the sky during aflight, and in cluding a horizon, and gyroscopic means for operating the roller means to move the screen from left to right and vice versa in co-relatedindica- 'form of the wing of an aircraft pivoted upon an axis lying between its ends mounted upon said supporting frame to assume tipped relation there trolled means for bodily moving said surface from to, a gyroscope a precessing'frame mounted for response-tobanked turns of the aircraft, and means gearing t wing-like' 'ifidicator so hat the indicator will tip in the field of view of the pilot in the same tipprecessing frame with the ping direction as the aircraftto which the instrument is attached and in such manner as to disgree as the bank angle of the aircraft upon which the instrument is used.

13. A flight indicator for aircraft comprising, means for representing a miniature aircraft. means for representing pictoriallly an artificial horizon positioned behind said aircraft, means for mounting said representation means for relative angular and translatory movements respectively, one of said mounting means being responsive to banking movement in flight and the other of said mounting means being responsive to pitching movement in flight whereby said representation means will indicate the relative attitude and path of movement of the supporting airing/aircraft in flight durin said slip.

DUDLEY )B. HOWARD. KENNETH B. WOLFE. 

